| 摘要 |
PROBLEM TO BE SOLVED: To reduce the cost of a magnetic bearing system for gas discharge lasers. SOLUTION: A discharge gas laser having a laser gas-containing laser cavity and a laser gas circulating fan 46 are provided. The fan is supported by an active radial magnetic bearing system and driven by a brushless DC motor, the rotor 134 of the motor and rotors of at least two radial bearings are sealed within a gas atmosphere of the laser cavity, the motor stator and the coils of the bearing magnets are disposed outside the gas atmosphere. No thrust bearing is provided. Positioning the shaft in the axial direction thereof is provided by a reluctance centering, made by at least two radial magnetic bearings 20, 22 and the brushless DC motor. It is preferable that the motor stator be made larger than the rotor in the axial direction, to enhance the magnetic centering effect. |
